1. Field of the Invention
This invention relates to a new valve construction and to a new method of making the same.
2. Prior Art Statement
It is known to provide a valve construction having an annular valve seat means and a movable valve member for opening and closing the valve seat means and being operatively interconnected to a thermal power element that is carried by the valve construction, the valve member having an annular rigid part for engaging the valve seat means and having an annular flexible part for also engaging the valve seat means at a point upstream of the rigid part. The parts of the valve member are so constructed and arranged that the rigid part moves out of engagement with and away from the valve seat means a certain distance before the flexible part moves out of engagement with the valve seat means. For example, see the U. S. patent of Sliger et al, U.S. Pat. No. 4,257,553 as well as FIGS. 1-4 of this application.
It is also known to provide a fixed leak notch in the poppet valve member or the valve seat means of a valve construction to provide a path for air to be dispelled during coolant filling operations of the engine cooling system utilizing such valve construction. For example, see the U.S. patent to Sliger, U.S. Pat. No. 4,091,991.
It is also known to attempt to decrease the rate of coolant flow with increasing temperature after the start-to-open point of a valve construction by shaping the valve seat means in relation to the edge of the valve member.